The spine consists of a series of vertebrae between each of which is a connective tissue pod termed a disc. Each vertebra is an irregularly shaped bone that consists of two parts: an anterior segment (front) and a posterior portion (neural arch). When the vertebrae and discs are in normal healthy condition they form a strong pillar for the support and shock absorption of the head and trunk, as well as forming a canal for the protection of the spinal cord.
Every vertebra also includes two transverse processes and one spinous process. These processes are posterior to the vertebrae, with the spinous process coming out of the back of the vertebrae and the transverse processes coming out the back of the vertebrae to the left and right of the spinous process.
Injury to a vertebra may occur through a wide number of avenues; one common injury is vertebral compression fracture. Vertebral compression fractures are a compression or squishing of a vertebra into a smaller height. Compression fractures are most common in patients that have suffered a traumatic accident, especially where the patient is elderly, and in patients with osteoporosis due to the vertebrae's bone loss or thinning.
Conventional treatment for a patient with a compression fracture is typically targeted at alleviating pain associated with the damaged vertebra. Pain management is typically through a combination of rest, pain medication(s), external bracing, stretching, and strengthening regimens. However, in some cases, more aggressive treatment is required when the vertebral collapse is severe or the pain unmanageable. In such cases a procedure known as “vertebroplasty” is utilized by directly injecting bone cement into the damaged vertebra to stabilize the fracture and prevent further collapse. Another procedure is “Kyphoplasty” where a balloon is placed into the fracture site and blown up to elevate the fracture. The balloon is removed and bone cement used to fill the void and hold all or some of the elevation at the fracture site.
Other techniques for treating compression fractures include wafer stacking or bag insertion into a compressed vertebra in order to elevate the bone until the vertebra is rigid, as well as other like procedures. Concerns with the above techniques include patient re-injury, where, over time, the originally injured vertebra or adjacent vertebrae undergo additional fracture. As proposed in the present disclosure, these injuries can be due to a difference in the modulus of these devices and materials from the modulus of cancellous bone, allowing for increased stress on the bone and adjacent vertebrae. This increase in bone stress can result in enhanced risk for re-injury to the vertebra or injury to a new adjacent area, i.e., the injured vertebra and adjacent vertebrae. Further, conventional therapies rely on injection and elevation of the vertebra under load conditions, i.e., the volume of the injected material is placed while the fracture site is not actively being reduced. Such methods have limited success in reproducing full elevation of the fracture, and rather have focused on stabilizing the fracture site and thereby reducing pain to the patient.
Therefore, there is a need in the art to provide alternative therapeutics for treatment of compression and other like fractures, and in particular to provide therapeutic compositions and methods that result in the placement of a stabilizing material while the fracture is being activity reduced as well as minimizing the risk of re-injury to the site or adjacent sites after treatment.
The present invention is directed toward overcoming one or more of the problems discussed above, especially in relation to techniques for addressing compression fractures in vertebrae.